In connection with such a measuring device, a pH value sensor or a temperature sensor is, for example, provided as the sensor, which is submerged in a liquid, for example. The raw data measured by the sensor are initially processed by the sensor circuit in order to be transmitted thereafter as measured data to the computing unit. The computing unit can display the measured data on an associated monitor, for example, or can pass them on via an associated external communication system to other control and/or monitoring devices.
A multitude of programming commands, which are used for processing received measured data, have been stored in the computing unit. For example, it is possible to convert the measured data in the computing unit with the aid of the programming commands. In the computing unit it is also possible, for example, to compensate sensor-dependent variations of the measured data, for example to average them, by means of the programming commands. As a whole, it is achieved with the aid of the programming commands that, as mentioned, the measured data can be displayed on the monitor or forwarded via the external communications system.
The different measuring principles of different sensors in particular result in that, on the one hand, the sensor circuits which are a part of the sensors are respectively differently constructed and that, on the other hand, the programming commands for processing the measured signals produced by the respective sensors and sensor circuits are also different.
Altogether this results in that not only a multitude of sensor circuits must be available for a multitude of sensors, but also a multitude of computing units with the respectively associated programming commands. This is extremely expensive, in particular in view of the resultant multitude of combination possibilities and the resultant management and storage of the individual components.
It is an object of the present invention to create a measuring device for determining physical and/or chemical properties of gases, liquids and/or solids, which is simpler and more cost- effectively constructed.
This object is attained by the present invention in connection with a measuring device of the type mentioned at the outset, in that an interchangeable program module in the computing unit is associated with the sensor circuit.
Thus, the present invention makes available a modularly constructed measuring device, which can be equipped with the respectively associated program module as a function of the employed sensor. It is therefore no longer required to produce, and in particular to store, a special, associated computing unit for each sensor, instead, based on the present invention it is possible to retain only a single computing unit, which can be used for all sensors with the aid of the program modules associated with the different sensors. Therefore, by means of the modularity in accordance with the present invention, the structure of the measuring device, and in particular its management and storage capability, is considerably simplified. This results in direct cost advantages.
On the one hand, the present invention can be realized by the computing unit to be connected with only a single sensor circuit, and therefore with only a single sensor. In this case it is necessary to load the program modules associated with the sensor into the computing unit. If at a later time it is intended to use a different type of sensor, this is possible in that the sensor with the associated sensor circuit is exchanged, that the program module is also removed, and that the program module associated with the new sensor is loaded into the computing unit.
In an advantageous embodiment of the present invention, two or more sensor circuits are provided, to each of which an exchangeable program module is assigned in the computing unit. Thus, in this case the computing unit is connected with two or more sensor circuits and therefore with two or more sensors. For the realization of such a measuring device it is necessary to connect the sensors with the associated sensor circuits to the computing unit and to load the program modules associated with the sensors into the computing unit. If at a later time it is intended to exchange one of the sensors with the associated sensor circuit, this is easily possible in that the associated program module is also replaced by the program module associated with the new sensor.
It is achieved by means of the following described advantageous embodiment of the present invention, that the program modules in the computing unit are not only arbitrarily exchangeable, but can also be enlarged as desired. A measuring device is created in this way, in which the number and types of sensors can be selected completely freely. With this embodiment it is also not necessary to retain a specific computing unit for each combination possibility of the measuring device. Instead, the already available computing unit can also easily be used for this embodiment in that the respective program module is loaded into the computer.
A control circuit for coupling respectively one of the sensor circuits with the computing unit is provided in an advantageous further embodiment of the present invention, wherein a program module in the computing unit is associated with the control circuit. If several sensor circuits are connected with the computing unit, the transmissions from the individual sensor circuits to the computing unit must be controlled, the control circuit, which in particular can be designed in the form of a multiplexer, is provided for this purpose. It is furthermore necessary for the control circuit itself to be controlled. For example, the control circuit must be set for the number of sensors which are connected in a particular application. A program module in the computing unit is associated with the control circuit for this purpose. For example, the control circuit is initialized and, if necessary additionally monitored, with the help of the program module.
It is particularly advantageous for the program module associated with the control circuit to be exchangeably embodied. In this case it is possible that the program module is only loaded into the computing unit if several sensors are connected to the computing unit. But if only one sensor is coupled with the computing unit, and if therefore the control circuit is not needed at all, it is possible because of the exchangeability to omit the loading into the computing unit of the program module associated with the control circuit.
In advantageous further developments of the present invention, at least one external communication system, or respectively at least one voltage supply, or respectively an interface, are provided, with which respectively one program module is associated in the computing unit. A completely modularly constructed measuring device is created in this way. Respectively one program module is associated with each one of the mentioned components, i.e. the external communication system, the voltage supply and the interface. In this regard it is therefore also not necessary to produce a special computing unit for each combination possibility, and in particular to store it. Instead, the already provided computing unit can be used, which, by the loading of the respective program module, is enabled to work together with the associated component.
In simple terms this means that each hardware component is associated with a software module in the measuring device in accordance with the present invention. If for a specific application it is necessary to provide the measuring device with a defined number and with defined types of sensors, this can be achieved in that the required hardware components are connected to the computing unit, and that the software modules associated with the hardware components are loaded into the computing unit. In this way the measuring device is individually tailored to the specific case of application. Only the hardware components and software modules necessary for this application are present in the measuring device. Especially there are no program commands provided in the computing unit, since they are not required for the present application. This provides the advantage that a customer can completely freely assemble a measuring device required for his defined application. It simultaneously provides the advantage that in spite of the mentioned freedom, the measuring device assembled in this manner only contains the actually required components and therefore can be produced in a cost-effective manner.
In connection with an advantageous embodiment of the present invention, the computing unit and the voltage supply and/or the interface are realized by means of a personal computer. Thus, no separate construction of the computing unit is required, instead the employment of a commercially available personal computer is sufficient. By means of this it is possible to considerably lower the costs of the measuring device in accordance with the present invention.
In this case it is advantageous if the personal computer is provided for executing further tasks. For example, it is possible to use the personal computer for controlling a process or the like, of which the measuring device of the present invention is a component. Here, the personal computer is simultaneously used for measurement and for controlling the same process.
In an advantageous embodiment of the present invention, the program module associated with a component is provided for performing all of the functions of the component. This means that the program module which, for example, is associated with a pH value sensor, contains all conversions, scaling, preparations of average values, etc., which are required for correctly and completely processing the measured data provided by the associated sensor circuit. In this way it is assured that, if for example the mentioned pH value sensor is used in the measuring device, by loading the associated program module all necessary steps have been taken so that the pH value sensor can work together with the computing unit.
A program module for controlling the other program modules is provided in connection with an advantageous embodiment of the present invention. This program module is, in other words, the central unit of the measuring device, from which the other program modules, and therefore the connected sensors, communication systems, etc., are controlled. In this case, control is generally understood to be the management, monitoring, etc., required for the correct functional operation of the measuring device. To a certain extent the so-called central program module is a sort of operating system of the computing unit and therefore of the measuring device.
In an advantageous further development of the present invention, each one of the program modules has a defined interface. In this way it is achieved and assured that the program module can be exchanged and/or expanded without effort.
In a further advantageous embodiment of the present invention, each program module constitutes an object in the sense of object- oriented programming. It is essentially automatically achieved by means of the mentioned object-oriented programming that at least one software module is associated with each hardware component. The modular structure of the measuring device created by the present invention is dependably and completely achieved in this way by the object-oriented programming.
In connection with a particularly advantageous embodiment of the present invention, the data associated with one of the components, in particular component-specific compensation data or the like, are stored in the component.
Thus, the component-specific compensation data are not originally stored in the computing unit. Instead, they are stored in the respective component, i.e. either in the sensor itself or in the associated sensor circuit.
When the measuring device is put into operation, the computing unit now retrieves the component-specific compensation data from the sensor, for example. Thereafter these data are available in the computing unit and can therefore be taken into consideration by the computing unit in processing the measured data provided by the sensor.
If now the sensor suffers a defect, for example because of aging, the defective sensor can be easily replaced by a new sensor. The compensation data associated with the new sensor have again been stored in the sensor itself. When the new sensor is put in operation, these new compensation data are loaded into the computing unit, so that now the computing unit can process the measured data provided by the sensor on the basis of the new compensation data. An insertion of the compensation data into the computing unit is not required. Also, a calibration of the new sensor at the place where it is used is not necessary. It can already be calibrated when it is produced. The detected component-specific compensation data can also be stored in the sensor during its manufacture.
If the mentioned compensation data are stored not in the sensor, but in the sensor circuit, the exchange of the sensor circuit, or at least the exchange of the respective memory in the sensor circuit, for example a PROM or the like, is also required in case of a defective sensor.
The use of the measuring device in accordance with the present invention is particularly advantageous in liquid and/or gas analyses, and/or when measuring moisture in liquids and/or gases.
Further characteristics, application possibilities and advantages of the present invention ensue from the following description of exemplary embodiments of the present invention represented in the drawings. Here, all described or represented characteristics constitute the subject of the present invention by themselves or in any arbitrary combination, regardless of their combination in the claims or their dependencies, as well as regardless of their wording, or respectively representation, in the description, or respectively in the drawings.